A typical color photographic element contains multiple layers of light-sensitive photographic silver halide emulsions, where one or more of these layers is spectrally sensitized to blue light, green light, and red light, respectively. The blue, green, and red light sensitive layers will typically contain, respectively, yellow, magenta, and cyan dye-forming couplers.
For forming color photographic images, the color photographic element is exposed imagewise and processed in a color developer bath containing an aromatic primary amine color developing agent. Generally, image couplers are selected to provide dyes showing good stability to heat and light and having an absorption spectrophotometric curve with a suitable peak absorption and low unwanted side absorptions, which results in color photographic images with good color reproduction.
The present invention is directed to yellow couplers that yield dyes of improved stability, particularly to conditions of elevated heat and humidity. Couplers that form yellow dyes upon reaction with oxidized color developing agents, typically open chain ketomethylene compounds, are described in such representative patents and publications as U.S. Pat. Nos. 2,298,443; 2,407,210; 2,875,057; 3,048,194; 3,265,506; 3,447,928; 4,022,620; and 4,443,536; "Farbkuppler-eine Literatur Ubersicht," published in Agfa Mitteilungen, Band III, pp 112-126 (1961); T. H. James, editor, The Theory of the Photographic Process, Macmillan, N.Y., 1977, pages 354-356; and Research Disclosure No. 365, Item 36544, September 1994, Section X-B(6).
A problem to be solved is to provide yellow dye-forming couplers with high coupling activity and improved stability, in particular, resistance to degradation under conditions of high heat and/or humidity.